Proximity detector device with interconnect layers and related methods

ABSTRACT

A proximity detector device may include a first interconnect layer including a first dielectric layer, and first electrically conductive traces carried thereby, an IC layer above the first interconnect layer and having an image sensor IC, and a light source IC laterally spaced from the image sensor IC. The proximity detector device may include a second interconnect layer above the IC layer and having a second dielectric layer, and second electrically conductive traces carried thereby. The second interconnect layer may have first and second openings therein respectively aligned with the image sensor IC and the light source IC. Each of the image sensor IC and the light source IC may be coupled to the first and second electrically conductive traces. The proximity detector device may include a lens assembly above the second interconnect layer and having first and second lenses respectively aligned with the first and second openings.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No. 15/668,138, filed on Aug. 3, 2017, which application is a divisional of U.S. patent application Ser. No. 14/259,344, filed on Apr. 23, 2014, and entitled “Proximity Detector Device with Interconnect Layers and Related Methods,” which application claims the benefit of Chinese Patent Application No. 201310158554X, filed on Apr. 28, 2013, which applications are hereby incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to the field of image sensor devices, and, more particularly, to a proximity detector device and related methods.

BACKGROUND

Typically, electronic devices include one or more image sensor modules for providing enhanced media functionality. For example, the typical electronic device may utilize the image sensor modules for photo capturing and video teleconferencing. Some electronic devices include additional image sensor devices used for other purposes, such as a proximity detector.

For example, the electronic device may use the proximity detector to provide object distances for providing focusing adjustment to the camera purposed image sensor modules. In mobile device applications, the proximity detector may be used to detect when the user's hand is nearby, thereby quickly and accurately waking the device from a power saving sleep mode. Typically, the proximity detector comprises a light source directing radiation to a potential nearby object, and an image sensor receiving the radiation reflected off of the nearby object.

For example, U.S. Patent Application No. 2009/0057544 to Brodie et al, assigned to the present application's assignee, discloses an image sensor module for a mobile device. The image sensor module comprises a lens, a housing carrying the lens, and a lens cap over the lens and housing. The image sensor module includes a barrel mechanism for adjusting the lens. During manufacture of an electronic device including one or more image sensor modules, there is a desire to manufacture the electronic device as quickly as possible, particularly in mass production runs.

The typical image sensor module is manufactured in a multi-step process. The first steps include semiconductor processing to provide the image sensor integrated circuit (IC). The next steps include some form of testing for the image sensor IC and packaging. The image sensor IC may be assembled into the image sensor module, along with a lens and movable barrel if needed. This assembly of the image sensor module may be performed manually or via machine. For example, in electronic devices that use surface mounted components, a pick-and-place (P&P) machine may assemble the components onto a printed circuit board (PCB). A drawback to such singular packaging is that it may be relatively inefficient and also may require that each device be tested individually, adding to the manufacturing time.

An approach to an image sensor is disclosed in U.S. Patent Application Publication No. 2012/0248625 to Coffy et al., assigned to the present application's assignee. This image sensor comprises a transparent support, a pair of ICs on the transparent support, and encapsulation material on the transparent support and surrounding the pair of ICs.

Referring now to FIG. 1, a proximity detector 20, as in the prior art, includes a dielectric layer 26, an image sensor IC 24 on the dielectric layer, a light source device 22 also on the dielectric layer, and an adhesive material 25 between the image sensor IC and the dielectric layer. The proximity detector 20 includes a cap 21 positioned on the dielectric layer 26 and having a plurality of openings 31, 32 a-32 b therein, and transparent adhesive material 23 covering the light source device 22. The proximity detector 20 also includes a lens 27 carried by the cap 21, and a plurality of wire bonds 29 a-29 c coupling the image sensor IC 24 and the light source device 22 to electrically conductive traces on the dielectric layer 26. The proximity detector 20 also includes additional transparent adhesive material 28 between the image sensor IC 24 and the lens 27. A potential drawback to this proximity detector 20 includes a multi-step high precision assembly process using a P&P device. Also, the proximity detector 20 may be less reliable and difficult to integrate into mobile devices, due to size constraints.

SUMMARY

In view of the foregoing background, it is therefore an object of the present disclosure to provide a proximity detector device that is efficient to manufacture.

This and other objects, features, and advantages in accordance with the present disclosure are provided by a proximity detector device comprising a first interconnect layer comprising a first dielectric layer, and a plurality of first electrically conductive traces carried thereby, an IC layer above the first interconnect layer and comprising an image sensor IC, and a light source IC laterally spaced from the image sensor IC. The proximity detector may comprise a second interconnect layer above the IC layer and comprising a second dielectric layer, and a plurality of second electrically conductive traces carried thereby. The second interconnect layer may have first and second openings therein respectively aligned with the image sensor IC and the light source IC. Each of the image sensor IC and the light source IC may be coupled to the pluralities of first and second electrically conductive traces. The proximity detector may comprise a lens assembly above the second interconnect layer and comprising first and second lenses respectively aligned with the first and second openings. Advantageously, the proximity detector may be manufactured using robust wafer level processing techniques and have a reduced size.

In particular, the IC layer may comprise encapsulation material laterally surrounding the image sensor IC and the light source IC. The encapsulation material may comprise a plurality electrically conductive vias, each coupled between a respective aligned pair of the pluralities of first and second electrically conductive traces.

The proximity detector device may further comprise transparent adhesive material in the first and second openings of the second interconnect layer. In some embodiments, the lens assembly may further comprise a molding compound surrounding the first and second lenses, and having first and second openings aligned with respective ones of the first and second lenses.

Additionally, the proximity detector device may further comprise a plurality of contacts coupled respectively to the plurality of first electrically conductive traces. For example, the plurality of contacts may comprise a plurality of ball grid array (BGA) contacts. The first lens may comprise a filter lens. The light source IC may comprise a light emitting diode.

Another aspect is directed to a method of making a proximity detector device. The method may comprise forming a first interconnect layer comprising a first dielectric layer, and a plurality of first electrically conductive traces carried thereby, forming an IC layer above the first interconnect layer and comprising an image sensor IC, and a light source IC laterally spaced from the image sensor IC. The method may include forming a second interconnect layer above the IC layer and comprising a second dielectric layer, and a plurality of second electrically conductive traces carried thereby. The second interconnect layer may have first and second openings therein respectively aligned with the image sensor IC and the light source IC. Each of the image sensor IC and the light source IC may be coupled to the pluralities of first and second electrically conductive traces. The method may also include forming a lens assembly above the second interconnect layer and comprising first and second lenses respectively aligned with the first and second openings.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic cross-sectional view of a proximity detector device, according to the prior art.

FIG. 2 is a schematic cross-sectional view of a proximity detector device, according to the present disclosure.

FIG. 3 is a flowchart of a method for making the proximity detector device of FIG. 2.

FIGS. 4-13 are schematic cross-sectional views of steps for making the proximity detector device of FIG. 2.

FIGS. 14-16 are schematic cross-sectional views of steps for making another embodiment of the proximity detector, according to the present disclosure.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The present embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the present disclosure are shown. This present embodiments may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present embodiments to those skilled in the art. Like numbers refer to like elements throughout, and prime notation is used to indicate similar elements in alternative embodiments.

Referring initially to FIG. 2, a proximity detector device 40 according to the present disclosure is now described. The proximity detector device 40 illustratively includes a first interconnect layer 41 comprising a first dielectric layer 45, and a plurality of first electrically conductive traces 48 a-48 b carried thereby. The proximity detector device 40 illustratively includes an IC layer 42 above the first interconnect layer 41 and comprising an image sensor IC 56, and a light source IC 55 laterally spaced from the image sensor IC. The light source IC 55 may comprise a light emitting diode (LED), such as an infrared LED.

The proximity detector device 40 illustratively includes a second interconnect layer 43 above the IC layer 42 and comprising a second dielectric layer 46, and a plurality of second electrically conductive traces 51 a-51 b carried thereby. The second interconnect layer 43 illustratively includes first openings 62 a-62 b and a second opening 61 therein respectively aligned with the image sensor IC 56 and the light source IC 55. Each of the image sensor IC 56 and the light source IC 55 is coupled to the pluralities of first 48 a-48 b and second 51 a-51 b electrically conductive traces.

In the illustrated embodiment, the first openings 62 a-62 b are illustratively aligned with the image sensor IC 56. The pair of first openings 62 a-62 b provides the imaging sensor IC 56 with access to the first and second lenses cavities.

The proximity detector device 40 illustratively includes a lens assembly 44 above the second interconnect layer 43. The lens assembly 44 illustratively includes first 53 and second 52 lenses respectively aligned with the first openings 62 a-62 b and the second opening 61.

In particular, the IC layer 42 includes encapsulation material 47 laterally surrounding the image sensor IC 56 and the light source IC 55. The encapsulation material 47 illustratively includes a plurality electrically conductive vias 50 a-50 b passing therethrough. Each electrically conductive via 50 a-50 b is coupled between a respective aligned pair of the pluralities of first 48 a-48 b and second 51 a-51 b electrically conductive traces.

The proximity detector device 40 illustratively includes transparent adhesive material 54 a-54 b in the first openings 62 a-62 b and the second opening 61 of the second interconnect layer. In the illustrated embodiment, the lens assembly 44 includes a molding compound 57 surrounding the first 53 and second 52 lenses. The lens assembly 44 illustratively includes first openings 59 a-59 b and a second opening 58 aligned with respective ones of the first 53 and second 52 lenses. In the illustrated embodiment, the first openings 59 a-59 b are aligned with the first lens 53.

Additionally, the proximity detector device illustratively includes a plurality of contacts 49 a-49 b (FIG. 16) coupled respectively to the plurality of first electrically conductive traces 48 a-48 b. For example, the plurality of contacts 49 a-49 b (FIG. 16) may comprise a plurality of BGA contacts. The first lens 53 may comprise a filter lens (e.g. glass filter or transparent sheet with filter coating). The first lens 53 may also comprise a focusing element in addition or alternatively.

Another aspect is directed to a method of making a proximity detector device 40. The method may comprise forming a first interconnect layer 41 comprising a first dielectric layer 45, and a plurality of first electrically conductive traces 48 a-48 b carried thereby. The method may include forming an IC layer 42 above the first interconnect layer 41 and comprising an image sensor IC 56, and a light source IC 55 laterally spaced from the image sensor IC. The method may include forming a second interconnect layer 43 above the IC layer 42 and comprising a second dielectric layer 46, and a plurality of second electrically conductive traces 51-51 b carried thereby. The second interconnect layer may have first openings 62 a-62 b and a second 61 opening therein respectively aligned with the image sensor IC 56 and the light source IC 55, each of the image sensor IC and the light source IC being coupled to the pluralities of first 48 a-48 b and second 51-51 b electrically conductive traces. The method may also include forming a lens assembly 44 above the second interconnect layer 43 and comprising first 53 and second 52 lenses respectively aligned with the first openings 62 a-62 b and the second opening 61.

Referring now additionally to FIGS. 3-16, a flowchart 70 illustrates a method for making the semiconductor device 20 (Block 71). In the illustrated embodiments, a wafer level processing technique for making a pair of identical proximity detector devices 40 is shown, but it should be appreciated that typical processes would include the manufacture of a large number of proximity detector devices (sometimes including varying embodiments in a single manufacturing process, i.e. the illustrated adjacent proximity detectors need not be identical). The method includes forming a carrier layer 90, and an adhesive layer 91 on the carrier layer (FIG. 4 and Block 73). The method includes positioning image sensor ICs 56 and light source ICs 55 on the adhesive layer 91 (FIG. 5 and Block 74). At this point, any other desired surface mount devices (e.g. capacitors) may also be positioned. The method includes forming an encapsulation material 47 on the image sensor ICs 56 and light source ICs 55 to define an IC layer 42 (FIG. 6 and Block 75).

The method includes flipping the IC layer 42 on the carrier layer 90 by heating the adhesive layer 91 to detach the IC layer and reapplying the IC layer to the adhesive layer on an opposite face thereof (FIG. 7 and Block 77). The method also includes forming a second interconnect layer 43 and a plurality of second electrically conductive traces 51 a-51 b carried thereby (FIG. 8 and Block 78).

The method includes forming a transparent adhesive material 54 a-54 b in first openings 62 a-62 b and the second opening 61 of the second interconnect layer 43. The method also includes positioning first 53 and second 52 lenses on the transparent adhesive material 54 a-54 b (FIG. 9 and Block 79).

The method includes forming molding compound 57 on the first 53 and second 52 lenses to define a lens assembly 44 (FIG. 10 and Block 80). In some embodiments, the forming of the molding compound 57 may be film assisted. The method includes flipping the IC 42 and second interconnect layers 43, and lens assembly 44 on the carrier layer 90 (FIG. 11 and Block 81) (again using a heating step to deactivate the adhesive layer 91). The method includes grinding a portion of the backside of the IC layer 42 (FIG. 12 and Block 82).

The method includes forming a first interconnect layer 41 comprising a first dielectric layer 45, and a plurality of first electrically conductive traces 48 a-48 b carried thereby (FIG. 13 and Block 84). In this embodiment, the plurality of first electrically conductive traces 48 a-48 b defines LGA contacts. The method also includes a singulation step (FIG. 15) (Blocks 84-86).

Advantageously, the proximity detector device 40 may be manufactured using robust wafer level processing techniques. Additionally, the proximity detector device 40 may be made in large quantities. Moreover, the structure is mechanically robust since the first 53 and second 52 lenses are tightly integrated with the lens assembly molding compound 57. Also, the lens assembly 44 is tightly integrated with the first 41, second 43 interconnect layers and the IC layer 43, also adding mechanical rigidity. The packaging of the proximity detector device 40 is thinner than typical approaches, thereby permitting easier integration into mobile devices. Moreover, the proximity detector device 40 provides for good co-planarity for the image sensor and light source ICs 55-56, thereby reducing the computational load of proximity detection calculations (i.e. from having adjacent source and receiver positions).

Referring now additionally to FIGS. 14-16, steps from another embodiment of the method for making the proximity detector device 40′ is now described. In this embodiment of the method for making the proximity detector device 40′, those steps and elements already discussed above with respect to FIGS. 2-13 are given prime notation and most require no further discussion herein. This embodiment differs from the previous embodiment in that this method illustratively includes forming a plurality of ball grid array contacts 49 a′-49 b′ on the plurality of first electrically conductive traces 48 a′-48 b′ (FIG. 14 and Block 85). The method illustratively includes a singulation step using a dicing blade 97′ (FIGS. 15-16).

Many modifications and other embodiments of the present disclosure will come to the mind of one skilled in the art having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is understood that the present disclosure is not to be limited to the specific embodiments disclosed, and that modifications and embodiments are intended to be included within the scope of the appended claims.

While this invention has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications and combinations of the illustrative embodiments, as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to the description. It is therefore intended that the appended claims encompass any such modifications or embodiments. 

What is claimed is:
 1. A method of forming a proximity detector device, the method comprising: forming a first interconnect layer comprising a plurality of first electrically conductive traces; forming an integrated circuit (IC) layer over the first interconnect layer, the IC layer comprising: an image sensor IC; and a light source IC laterally spaced from the image sensor IC; forming a second interconnect layer over the IC layer, the second interconnect layer comprising a plurality of second electrically conductive traces and first and second openings having sidewalls defined by dielectric material of the second interconnect layer, the first and second openings respectively aligned with the image sensor IC and the light source IC; filling the first and second openings of the second interconnect layer with a transparent adhesive material, the transparent adhesive material physically contacting the image sensor IC and light source IC; forming a lens assembly over the second interconnect layer, the lens assembly comprising first and second lenses respectively aligned with the first and second openings and adhered to the transparent adhesive material; and forming a plurality of contacts coupled respectively to the plurality of first electrically conductive traces.
 2. The method of claim 1, wherein the forming of the IC layer comprises: forming an adhesive layer over a carrier; placing the image sensor IC and the light source IC over the adhesive layer; and forming encapsulation material to laterally surround the image sensor IC and the light source IC, wherein a first major surface of the encapsulation material is directed away from the carrier, and wherein a second major surface of the encapsulation material physically contacts the adhesive layer.
 3. The method of claim 2, wherein the forming of the IC layer further comprises: detaching the IC layer from the carrier after forming the encapsulation material; flipping the IC layer; and reattaching the IC layer to the adhesive layer, wherein the first major surface of the encapsulation material physically contacts the adhesive layer after the reattaching.
 4. The method of claim 1, wherein the forming of the lens assembly further comprises: forming a molding compound to surround the first and second lenses; and forming third and fourth openings respectively aligned with the first and second lenses.
 5. The method of claim 1, wherein the plurality of contacts comprises a plurality of ball grid array (BGA) contacts.
 6. The method of claim 1, wherein the light source IC comprises a light emitting diode.
 7. A method of forming a proximity detector device, the method comprising: positioning an image sensor integrated circuit (IC) and a light source IC on an adhesive layer of a carrier layer, wherein the image sensor IC and the light source IC are laterally spaced apart; forming an encapsulation material to surround the image sensor IC and the light source IC to form an IC layer on the carrier layer, wherein a backside of the encapsulation material is directed away from the carrier layer; flipping the IC layer and placing the IC layer on the carrier layer after forming the encapsulation material; forming an interconnect layer over the encapsulation material, wherein the interconnect layer comprises electrically conductive traces coupled to contacts of the image sensor IC and contacts of the light source IC, the interconnect layer further comprising first and second openings respectively aligned with the image sensor IC and the light source IC; forming a transparent adhesive material in the first and second openings; positioning a first lens and a second lens on the transparent adhesive material, the first lens and the second lens physically contacting the transparent adhesive material and respectively aligned with the image sensor IC and the light source IC; forming a molding compound over the interconnect layer to surround the first lens and the second lens, wherein the IC layer, the interconnect layer, and the molding compound surrounding the first lens and the second lens form an intermediate structure; flipping the intermediate structure and placing the intermediate structure on the adhesive layer of the carrier layer, wherein the backside of the encapsulation material is directed away from the carrier layer after flipping the intermediate structure; removing a portion of the backside of the encapsulation material to expose surfaces of the image sensor IC and the light source IC; forming a further interconnect layer over the IC layer, the further interconnect layer comprising further electrically conductive traces electrically coupled to the electrically conductive traces of the interconnect layer; and forming a plurality of contacts coupled to the further electrically conductive traces of the further interconnect layer.
 8. The method of claim 7, wherein flipping the IC layer and placing the IC layer on the carrier layer comprises heating the adhesive layer, detaching the IC layer from the adhesive layer, flipping the IC layer, and reattaching the IC layer onto the adhesive layer so that the backside of the encapsulation material is directed toward the carrier layer after flipping the IC layer.
 9. The method of claim 7, wherein forming the further interconnect layer over the IC layer comprises forming vias in the IC layer, wherein the vias are electrically coupled to the electrically conductive traces of the interconnect layer, and forming the further electrically conductive traces over the IC layer, wherein the further electrically conductive traces are electrically coupled to the vias in the IC layer.
 10. The method of claim 7, further comprising a singulation process to separate the proximity detector device from an adjacently-formed proximity detector device.
 11. The method of claim 7, wherein the plurality of contacts comprises a plurality of ball grid array (BGA) contacts.
 12. The method of claim 7, wherein removing the portion of the backside of the encapsulation material to expose surfaces of the image sensor IC and the light source IC comprises grinding the backside of the encapsulation material.
 13. The method of claim 7, wherein the first lens comprises a filter lens.
 14. The method of claim 7, wherein the first lens comprises a focusing element.
 15. The method of claim 7, wherein the light source IC comprises a light emitting diode.
 16. The method of claim 15, wherein the light emitting diode comprises an infrared light emitting diode.
 17. The method of claim 7, wherein forming the transparent adhesive material in the first and second openings comprises filling the first and second openings with the transparent adhesive material, the transparent adhesive material extending out of the first and second openings of the interconnect layer. 